The Communications Assistance for Law Enforcement Act of 1994 (CALEA) requires telecommunications network providers to provide means for a law enforcement agency to intercept communications occurring over their network when presented with a valid court order. In complying with this requirement, telecommunications providers duplicate the communications associated with a surveillance target, i.e., the person that is the subject of a wiretap order, and deliver the duplicated communications to the law enforcement agency, e.g., the Federal Bureau of Investigation (FBI). However, there are drawbacks with the process of duplicating communications of a surveillance target and providing all of the communications of a surveillance target to the law enforcement agency.
In the current methodology used, all of the communications of a surveillance target are duplicated by the telecommunications provider and delivered to the law enforcement agency. Thus, even if a particular communication of the surveillance target is not directed to the subject matter of the wiretap order, the communication is still duplicated by the telecommunications provider and delivered to the law enforcement agency. It is then the law enforcement agency's responsibility to initially monitor the communication to determine if the subject matter of the communication is within the limits authorized by the wiretap order. If the subject matter of the communication is within the scope of the order, then the law enforcement agency is authorized to further monitor the communication. If the subject matter is not within the scope of the order, the agency must cease monitoring the communication. This requirement for the law enforcement agency to initially determine whether further monitoring is authorized under the wiretap order is generally referred to as “minimization”, as will be further described below.
In a wiretap order issued by a judicial officer, the right to wiretap comes with restrictions. Among these restrictions is a requirement for the law enforcement agency to minimize the amount of “listening” it performs. The order only authorizes monitoring of a communication by the law enforcement agency if the communication is related to the subject of the order, e.g., a particular crime that the target is suspected of committing. Therefore, the law enforcement agency must initially monitor the call to determine if it is directed to the subject matter of the wiretap order. The order may also specify the amount of time in which the law enforcement agency must make their determination as to the relevancy of the communication to the subject of the order. For example, the wiretap order issuing authority may specify a minimization time of 30 seconds. After 30 seconds, if the topic of the call is not related to the subject matter of the wiretap order, the law enforcement agency must stop monitoring the call. It may recommence the process on the next communication in the same manner.
This “minimization” process by the law enforcement agency has several drawbacks. First, minimization is not a verifiable activity. Because it is performed by law enforcement agents by physically listening to the communication as it occurs in near real-time, there is no clear record that the law enforcement agents adhered to the legal requirements for the wiretap. As a result, if the communication is monitored and offered as evidence in a trial, the evidence may be subject to attack by the subject as being obtained illegally. For example, the subject could argue that the agents listened beyond the authorized 30 seconds to determine that the call was directed to the subject matter of the order or argue that the content of the call within the minimization period did not authorize further monitoring.
Another drawback results from the minimization time constraints. The law enforcement agency only has a short period of time to determine if the call can be further monitored. A call that does not discuss the subject matter of the wiretap within the minimization period may eventually discuss this subject matter later in the call. However, because the law enforcement agency must make a further monitoring determination early in the call, this later relevant portion of the call may be lost as potential evidence. Even if law enforcement agents are permitted to again determine if the subject matter of the call is relevant to the order after an initial negative determination is made, the agents are still required to make their determination on discrete later portions of the call that may not be relevant even if other portions of the call may be relevant. In this circumstance, again, the relevant portion of the call may be lost as potential evidence.
Therefore, in a “content-wiretap” authorized under Title III of the Omnibus Crime Control and Safe Streets Act of 1968 (Title III), as discussed above, where the content of conversations can be monitored in near real-time, a law enforcement agency is basically presented with an “all-or-nothing” proposition. In a very short period of time after commencement of a conversation, or during discrete later portions of the conversation, the law enforcement agency must determine whether further monitoring is authorized. If it is, the call may be further monitored. If it isn't, the monitoring must cease, even if other portions of the call relate to the relevant issues. This loss of potential evidence is particularly troublesome where many of the factual situations are not clear cut.
This potential loss of relevant evidence is also a problem in “trap-and-trace” monitoring. The vast majority of wiretap orders, approximating 90 percent, only permit law enforcement to determine the time, place and parties involved in a call. This is known as a “trap-and-trace” warrant. Under this type of warrant, a law enforcement agency isn't permitted to hear the content of the speech. In this circumstance, the content of the communication is lost as potential evidence even if it is later determined that the more difficult to obtain Title III content-wiretap was permissible.
There are also drawbacks with the present method of performing wiretaps in the context of dispatch calls, or “walkie-talkie” calls, such as in Nextel Communication Inc.'s push-to-talk (PTT) technology. In a dispatch call, dispatch sessions are not full-duplex conversations and do not have a circuit dedicated to the call, even if it is a virtual circuit, as do circuit-switched calls. PTT sessions are simplex calls. Therefore, in dispatch calls, it is more difficult to monitor a conversation between two or more individuals because there is no dedicated circuit to monitor for the dispatch session. This same problem exists not only for dispatch calls, but also for any type of call that is not carried over a dedicated circuit or routed through a central switch, such as a call made by a cell phone roamer. In the case of a roamer who is not making calls in his home area when a wiretap order is executed, these calls will bypass interception. Only the calls to the subscriber that are routed to their home system will be capable of being monitored.
Another problem that may be particular to dispatch calls is that because no circuit is established for initiation of the dispatch session, and thus no circuit is torn down to clearly define the end of the session, it is difficult to determine when one particular dispatch session has ended and when another new session has begun. This presents problems for law enforcement agencies with respect to their minimization requirements because it may not be clear for a later dispatch session whether the session is part of an earlier session, and thus possibly not be authorized for further monitoring because of the non-relevancy of the earlier session, or whether it is a new session which can be initially monitored for at least the minimization time period.
Therefore, there is a need for an improved system and method for analyzing communications between a calling party and a called party, which would not only have application to the monitoring of communications by law enforcement agencies but also to other applications as well. With respect to law enforcement agency monitoring, the improved system and method could both protect the privacy of the individual being wiretapped and assure and verify compliance by law enforcement agencies to wiretap order requirements.